title: Oxidative stress response signaling pathways in trabecular meshwork cells and their effects on cell viability.
abstract: OBJECTIVE
  To clarify the primary oxidative stress response signaling pathways in trabecular meshwork (TM) cells and their effects on cell viability.
  
  
  METHODS
  Porcine TM cells were treated with 600 μM or 800 μM H₂O₂, and their time-dependent morphologic changes were observed. Phosphorylation of protein kinase B (Akt), extracellular regulated kinase (ERK)1/2, p38, and c-Jun NH2-terminal kinase (JNK) was evaluated by western blot analysis. The intracellular localization of NFκB was evaluated by western blot analysis. One-hour pretreatments with LY294002, U0126, and SB203580, with the inhibitors of PI3K, ERK1/2, and p38, respectively, were conducted to evaluate the roles of these molecules in the cellular reaction against H₂O₂. Cell viability was assessed using propidium iodide and anticleaved caspase-3 antibody.
  
  
  RESULTS
  TM cells treated with 600 μM H₂O₂ showed morphologic changes at 2 h that were partially recovered at 8 h after treatment. TM cells treated with 800 μM H₂O₂ did not recover, and the viability was significantly decreased. Both doses of H₂O₂ activated Akt, ERK1/2, and p38 in TM cells at 20 min after treatment, but not JNK or NFкB until 1 h after treatment. Inhibitors of PI3K, ERK1/2, and p38 suppressed recovery from the morphologic changes induced by 600 μM H₂O₂. Of these three inhibitors, the PI3K and ERK1/2 inhibitors decreased TM cell viability under oxidative stress.
  
  
  CONCLUSIONS
  In TM cells, the PI3K-Akt, ERK, and p38 signaling pathways are primary oxidative stress response pathways involved in the mechanism of recovery from cellular morphologic changes induced by H₂O₂ treatment accompanied by actin cytoskeletal changes.
authors.affiliation: Department of Ophthalmology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Nanako
authors.initials: N
authors.lastname: Awai-Kasaoka
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Inoue
authors.forename: Takanori
authors.initials: T
authors.lastname: Kameda
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Fujimoto
authors.forename: Miyuki
authors.initials: M
authors.lastname: Inoue-Mochita
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Tanihara
mesh_terms: D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000633:toxicity; D007093:Imidazoles / Q000494:pharmacology; D007150:Immunohistochemistry; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D034421:Sus scrofa; D013997:Time Factors; D059008:Time-Lapse Imaging; D014129:Trabecular Meshwork / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D002070:Butadienes; D002867:Chromones; D007093:Imidazoles; D009025:Morpholines; D009570:Nitriles; D011725:Pyridines; C113580:U 0126; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D006861:Hydrogen Peroxide; D051057:Proto-Oncogene Proteins c-akt; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580